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GPIB client listener/monitor

I currently have a PC which controls a vector network analyzer (VNA) through a GPIB bus. I need to monitor the communication taking place between the PC and the VNA from a different PC. I have connected (daisy chained) a GPIB-USB-B cable to the GPIB bus connecting the first PC to the VNA. How can this be implemented. I've tried to use the GPIB Read block but that interrupts the communication between the PC and the VNA. I want my second PC to be a secondary device and all I want it to do is to listen in on the communication taking place between the first PC and the VNA without interrupting it.

Any help would be really appreciated. Thanks in advance.
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Message 1 of 9
Hi Arthur,
why use a secondary PC?

Have you tried to use NI spy located in MAX (NI software)

Ni spy captures all traffic between the connected controller (PC) and the slaves.

i have found it extremely useful for debugging commands plus you also have the timing information.

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Message 2 of 9
Hey xseadog,

I need a secondary PC because the original PC is running off of a Windows 98 machine which has some legacy software controlling the VNA along with some other hardware. Therefore, we have no choice but to use a secondary PC. The secondary PC needs be aware of the GPIB communication taking place between the old PC and the VNA.

I tried to use NI Spy, but NI Spy itself interrupts the communication between the old PC and the VNA. Out of curiosity, even if I could get NI spy to work, would I be able to use the NI Spy features from within a LabVIEW program?

Do you have any other suggestions?

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Message 3 of 9
FOLLOW-UP: Ni website states "NI-Spy can only "spy" on data that is driven by NI drivers on a computer." Since my existing setup is not driven by Ni drivers, NI Spy is out of the question for me.

Does anyone have any other suggestions?

Message Edited by ArthurB on 03-12-2007 06:56 PM

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Message 4 of 9
If you just need to monitor, there are stand alone bus analyzers. NI's GPIB controllers with a + in the name (i.e. PCI-GPIB+), have a built-in analyzer that could be used.
Message 5 of 9
I looked at those but wasn't sure if they can only be used with the GPIB Analyzer program or can they be used from within LabVIEW. Do you know?
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Message 6 of 9
I don't think the NI analyzer can be used in LabVIEW. I've only used the analyzer as a diagnostic tool when debugging instrument drivers and have had no need to have another LabVIEW program look at the results. There may be a stand-alone analyzer out there that can be controlled but I'm not aware of one off-hand. What do you need to do with the GPIB traffic you need to capture?
Message 7 of 9
The GPIB traffic is going to be used as a trigger. I just need to detect when the host PC sends a command to the hardware and us that event as a trigger in my LabVIEW program.
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Message 8 of 9
Check this KB it might help you in what you were trying to do.
Good luck.
Nikhil A.
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Message 9 of 9